[GHC] #9898: Wanted: higher-order type-level programming

[GHC]

#9898: Wanted: higher-order type-level programming
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              Reporter:  erisco      |            Owner:
                  Type:  feature     |           Status:  new
  request                            |        Milestone:
              Priority:  normal      |          Version:  7.8.3
             Component:  Compiler    |         Keywords:
  (Type checker)                     |     Architecture:  x86_64 (amd64)
            Resolution:              |       Difficulty:  Unknown
      Operating System:  Windows     |       Blocked By:
       Type of failure:  GHC         |  Related Tickets:
  rejects valid program              |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by jstolarek):

 > Does applying a type family to no arguments count as being partially
 applied?
 Yes. To be more precise: you can't have *unsaturated* type families, where
 unsaturated means "applied to less arguments than it's arity".

 > will such usage be banned n 7.8.4?
 No. But that's still a bug and you shouldn't construct your code around
 this.

 > What is a good place for Q&A on type level programming in Haskell?
 Haskell-cafe.

 If you really want partial application at the type level you can try out
 `singletons`, as suggested by Richard.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9898#comment:5>
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